The present invention relates to a radio apparatus and, more particularly, to a radio telephone to be used as a portable or a vehicle-mounted telephone.
A conventional radio telephone is energized by a battery in portable use and by a vehicle battery in vehicle-mounted use. In both cases, a DC voltage is applied to a receiver section through a voltage stabilizer. The voltage to be applied to the receiver section is minimized to save the battery power in the portable use. As a result, in the vehicle-mounted use, receiver performance such as an intermodulation (IM) characteristic and reception sensitivity is sacrificed for the power saving. On the contrary, if the voltage is increased to improve the receiver performance, the life of the battery for portable use will be shortened.